The overall goal of this study is to investigate and document patterns of utilization of mental health services by children, adolescents and their parents in the Blue Cross/Blue Shield (BC/BS) Federal Employee Program (FEP) population over a 10 year period from 1974-1983, and to use the database of all mental health and medical claims for this population to test several major hypotheses regarding the utilization of mental health services by children and adolescents. Because the BC/BS FEP population represents a substantial portion (6.7 million individuals) of all medical and mental health care services consumed in the United States over a 10 year period, because the BC/BS benefits were extremely broad throughout these years, and because of the national scope of this database, this study offers the opportunity to describe, and test hypotheses about, patterns and interrelationships of mental health and physical health care utilization by children and adolescents. This area of study seems particularly important since there is relatively little existing information about the use of mental health services by children and since the limited information available indicates that children tend to be undeserved. There are three major aims of this study: (1) to describe comprehensively patterns of utilization of mental health and medical services by children, adolescents, and their parents in the BC/BS FEP population between 1974 and 1983; (2) to test a series of hypotheses regarding the probability that children or adolescents will use mental health services and the type and amount of such services that will be used and (3) to test the hypothesis that there is a cost-offset effect for children and/or adolescents when those who received mental health treatment are compared with a similar group (matched or adjusted for physical morbidity and other factors) who received no mental health care.